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Shoring, its objectives and types

Short answer

Shoring is temporary support to unsafe structures using inclined, horizontal, or vertical members to prevent collapse until permanent repair. Objectives include preventing wall collapse, supporting adjoining buildings during excavation, carrying loads during alterations, and ensuring safety. Types are raking shore (inclined from ground), flying shore (horizontal between walls), and dead shore (vertical posts with needles for vertical loads).

Define shoring. What are the objectives of shoring? Describe the types of shoring with necessary sketches.

Shoring is the temporary support given to an unsafe wall, building or structure to prevent it from collapsing, using inclined, horizontal or vertical timber or steel members, until permanent repair or reconstruction is done.

Objectives

  • To prevent the collapse of a weak, leaning or cracked wall.
  • To support adjoining buildings during demolition or excavation.
  • To support the structure above while the lower part is altered or underpinned.
  • To carry loads temporarily during repair or extension.
  • To keep people and property safe.

Types

1. Raking shore

Raking (inclined) shore: inclined members (rakers) support a wall from the outside. Rakers are at 60-70 degrees to the ground. At the top they bear on needles fixed through a wall plate that is secured to the wall, and at the bottom they rest on a sole plate on a firm base. Cleats and braces hold the members together.

        wall plate
   wall |==|\ needle
   |    |  | \ raker
   |    |  |  \ cleat
   |    |  |   \
   |    |  |    \
 --+----+--+-----\--- ground
                sole plate

Types: simple (single raker), compound/double (two or more rakers meeting the wall at different levels), and multiple raking shores for high walls (up to three storeys).

2. Flying shore

Flying (horizontal) shore: used when two parallel walls with a narrow gap (3-9 m) between them are to be supported, e.g. when the building between them is demolished. A horizontal shore is fixed between wall plates on the two walls, supported on needles, with inclined struts from lower needles up to straining pieces on the horizontal shore. No part touches the ground, hence "flying".

  wall                                      wall
  |  ||==N====== horizontal shore ======N==||  |
  |  ||     [sp]                  [sp]     ||  |
  |  ||      /                      \      ||  |
  |  ||    /   strut          strut   \    ||  |
  |  ||  /                              \  ||  |
  |  ||N/                                \N||  |
  |  ||                                    ||  |
  || = wall plate, N = needle, [sp] = straining piece

A single flying shore is used for gaps up to about 9 m; a double (compound) flying shore is used for wider gaps. The system is cheaper than raking shores and keeps the ground clear for work.

3. Dead shore

Dead (vertical) shore: used to support the floors and roofs above when a wall is removed, an opening is made in a lower storey, or the lower wall is repaired. It transfers the vertical load to the ground.

It consists of vertical posts (dead shores) on a sole plate at the bottom, a needle (horizontal beam) passing through the wall at the top, and braces, cleats and wedges to take up the weight.

        floor above
   ____|==needle==|____
   wall| |      | |wall
   wall| | post | |
   wall| | post | |
       |_|______|_|
       sole plate

✓ Answer checked by Claude Opus 5.5 (high effort)

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